Magnetic resonance spectroscopy (MRS) and functional magnetic resonance imaging (fMRI) are extraordinarily promising new imaging modalities that are increasing our understanding of the nature of drug abuse and addiction. In March, 1999, the Office of National Drug Control Policy (ONDCP) and McLean Hospital agreed to jointly fund a Varian NMR Systems 4.0 T MR scanner which will be dedicated to substance abuse research at the McLean Brain Imaging Center. The present BRP application describes a series of ten engineering projects which will enhance the capabilities of this unique magnetic resonance research center to conduct studies of individuals with substance abuse disorders. This research program will involve bioengineering and clinical investigators at McLean Hospital, the Beth Israel Hospital, Tufts University, Boston University, the University of Washington, the University of Oxford, the University of California, San Francisco, and Wayne State University. Specific projects are summarized below: 1. Objective motion detection and correction in time series fMRI experiments. 2. Optimized phased array coil design. 3. FMRI image registration and signal dropout reduction in brain regions with high susceptibility effects. 4. Functional T2 relaxometry of brainstem and midbrain monoaminergic nuclei. 5. Estimation of cerebral blood flow and volume using dynamic susceptibility contrast MRI. 6. Proton echo-planar spectroscopic imaging at 4 T. 7. Two-dimensional, proton magnetic resonance spectroscopy of amino acid neurotransmitters. 8. Statistical methods for assessing drug effects and confounds in MRS and fMRI studies. 9. Concurrent, high resolution optical imaging and fMRI. 10. Concurrent EEG and fMRI assessment of drug-induced alpha wave activity. All of the projects listed above have been have been designed to address technical limitations encountered in the course of conducting NIDA-funded clinical imaging studies at 1.5 T field strength. Importantly, funds requested for this BRP will be used exclusively to support the engineering aspects of the research projects.